Method and apparatus for applying revision specific electronic signatures to an electronically stored document

ABSTRACT

Aspects of the present disclosure are directed to methods and systems for applying electronic signatures to an electronically stored document wherein the electronic signatures are associated with a specific revision of that electronically stored document (revision specific electronic signatures).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 13/396,069, now U.S. Pat. No. 8,856,640, entitled “METHOD ANDAPPARATUS FOR APPLYING REVISION SPECIFIC ELECTRONIC SIGNATURES TO ANELECTRONICALLY STORED DOCUMENT,” filed on Feb. 14, 2012, which is acontinuation application of U.S. application Ser. No. 13/355,098, nowabandoned, entitled “METHOD AND APPARATUS FOR APPLYING REVISION SPECIFICELECTRONIC SIGNATURES TO AN ELECTRONICALLY STORED DOCUMENT,” filed onJan. 20, 2012, the disclosure of which is incorporated herein byreference.

TECHNICAL FIELD

This disclosure relates generally to electronically stored documents andin particular to methods and apparatus that provide revision specificelectronic signatures to electronically stored documents.

BACKGROUND

Generally, an electronic signature when applied to an electronicallystored document is an indication that a person who applied theelectronic signature approves of or otherwise adopts the document. Itis, in other words, electronic data that carries the intent of asignature. As such, electronic signatures may provide verification torecipients of the document that the content has not been altered(Integrity), that the document is coming from a trusted or known person(Authentication), and/or that the individual who has applied theelectronic signature cannot deny the signature (Non-repudiation).

SUMMARY

Briefly, aspects of the present disclosure are directed to methods andsystems for applying electronic signatures to an electronically storeddocument wherein the electronic signatures are associated with aspecific revision of that electronically stored document.

As used herein, an electronic signature is an electronic sound, symbol,or process attached to or logically associated with an electronicallystored document that is executed, approved or otherwise adopted by theapplier of the electronic signature. The term “electronic” meansrelating to technology having electrical, digital, magnetic, wireless,optical, electromagnetic or similar capabilities. A digital signature isbut one type of electronic signature.

This SUMMARY is provided to briefly identify some aspects of the presentdisclosure that are further described below in the DESCRIPTION. ThisSUMMARY is not intended to identify key or essential features of thepresent disclosure nor is it intended to limit the scope of any claims.

The term “aspects” is to be read as “at least one aspect”. The aspectsdescribed above and other aspects of the present disclosure describedherein are illustrated by way of example(s) and not limited in theaccompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

A more complete understanding of the present disclosure may be realizedby reference to the accompanying drawing in which:

FIG. 1 is schematic diagram depicting a prior art application of anelectronic signature to an electronically stored document;

FIG. 2 is a schematic diagram depicting a prior art application ofmultiple electronic signatures to an electronically stored document;

FIG. 3 is schematic diagram depicting the application of a revisionspecific electronic signature to an electronically stored documentaccording to an aspect of the present disclosure;

FIG. 4 is a schematic diagram depicting the application of a number ofrevision specific electronic signatures to an electronically storeddocument according to an aspect of the present disclosure;

FIG. 5 is a schematic diagram depicting the application of a number ofrevision specific electronic signatures to an electronically storeddocument according to an aspect of the present disclosure;

FIG. 6(a) is a schematic diagram depicting several revision specificelectronic signatures as applied to an electronically stored documentaccording to an aspect of the present disclosure;

FIG. 6(b) is a schematic diagram depicting a revision history table forthe electronically stored document of FIG. 6(a);

FIG. 7 is a schematic diagram depicting an exemplary user interfaceinteraction to apply a revision specific electronic signature to anelectronically stored document according to an aspect of the presentdisclosure; and

FIG. 8 is a schematic diagram depicting a representative computer systemfor implementing and exemplary methods and systems for modifying anelectronically stored document via modification of a table of contentsassociated with that document according to an aspect of the presentdisclosure.

The illustrative embodiments are described more fully by the Figures anddetailed description. The inventions may, however, be embodied invarious forms and are not limited to specific embodiments described inthe Figures and detailed description

DESCRIPTION

The following merely illustrates the principles of the disclosure. Itwill thus be appreciated that those skilled in the art will be able todevise various arrangements which, although not explicitly described orshown herein, embody the principles of the disclosure and are includedwithin its spirit and scope.

Furthermore, all examples and conditional language recited herein areprincipally intended expressly to be only for pedagogical purposes toaid the reader in understanding the principles of the disclosure and theconcepts contributed by the inventor(s) to furthering the art, and areto be construed as being without limitation to such specifically recitedexamples and conditions.

Moreover, all statements herein reciting principles, aspects, andembodiments of the disclosure, as well as specific examples thereof, areintended to encompass both structural and functional equivalentsthereof. Additionally, it is intended that such equivalents include bothcurrently known equivalents as well as equivalents developed in thefuture, i.e., any elements developed that perform the same function,regardless of structure.

Thus, for example, it will be appreciated by those skilled in the artthat any block diagrams herein represent conceptual views ofillustrative blocks or elements embodying the principles of thedisclosure. Similarly, it will be appreciated that any flow charts, flowdiagrams, state transition diagrams, pseudocode, and the like representvarious processes which may be substantially represented in a computerreadable medium and so executed by a computer or processor, whether ornot such computer or processor is explicitly shown.

The functions of the various elements shown in the Figures, includingany functional blocks labeled as “processors”, may be provided throughthe use of dedicated hardware as well as hardware capable of executingsoftware in association with appropriate software. When provided by aprocessor, the functions may be provided by a single dedicatedprocessor, by a single shared processor, or by a plurality of individualprocessors, some of which may be shared. Moreover, explicit use of theterm “processor” or “controller” should not be construed to referexclusively to hardware capable of executing software, and mayimplicitly include, without limitation, digital signal processor (DSP)hardware, network processor, application specific integrated circuit(ASIC), field programmable gate array (FPGA), read-only memory (ROM) forstoring software, random access memory (RAM), and non-volatile storage.Other hardware, conventional and/or custom, may also be included.

Software modules, or simply modules which are implied to be software,may be represented herein as any combination of flowchart elements orother elements indicating performance of process steps and/or textualdescription. Such modules may be executed by hardware that is expresslyor implicitly shown.

Unless otherwise explicitly specified herein, the drawings are not drawnto scale.

It is noted that an electronic signature generally refers to a mark orother indicia of some sort that is imputed into an electronically storeddocument through electronic means. As may be readily appreciated bythose skilled in the art, an electronically stored document is anyelectronic media that may be used in either an electronic form or as aprinted output. Electronically stored documents may be associatedwith—for example—word processing, spreadsheets, presentation graphics,technical or architectural drawings or plain text—among others.Electronically stored documents may exhibit any of a number of knownformats.

Oftentimes, a digital signature is used to implement an electronicsignature. Digital signatures advantageously employ a type ofcryptography and when properly implemented provide added assurances ofprovenance, identity and status of an electronically stored document aswell as acknowledging informed consent and approval by a signatory.

With reference to FIG. 1, there is shown a schematic diagram depicting aprior art method for affixing an electronic signature to anelectronically stored document. As depicted therein, an electronicallystored document 110 is shown having a signature line 120 for signing byan individual signor 130.

Generally, a signature line 120 in an electronically stored documentlooks like a signature placeholder that may appear in a printeddocument, but operates differently. When a signature line 120 is placedin an electronically stored document, an individual 130 may then applyhis/her electronic signature to the signature line 120 to electronicallysign the document.

As may be readily appreciated, the electronic signature may be appliedto the signature line 120 in any of a number of ways. For example, theindividual 130 may simply click on the signature line with a mouse orother input device and then use a keyboard or other input device to typea signature. Alternatively, the individual 130 may select and apply adigital image of his/her signature or another alternative indicia. Stillfurther, the individual 130 may actually sign the signature with apen/tablet/touch input device (not specifically shown).

Advantageously, an electronic signature may be visible, invisible or acombination of visible/invisible. Additionally, an electronic signaturemay include a cryptographic digital signature component as well. For thepurposes of this description, any electronic signatures shown in theFigures are depicted as a “ribbon” or “certificate” 125 and is generallyindicative of an electronic signature of any type described herein.

According to the prior art, once an electronically stored document iselectronically signed, it is read-only such that subsequent modificationto the electronically stored document is prevented.

Turning now to FIG. 2, there is shown a schematic diagram depicting aprior art method for applying multiple electronic signatures to anelectronically stored document. As depicted therein, an electronicallystored document 210 is shown having a number of signature lines 220,221, 222 for signing by a number of individual signers.

As may be readily appreciated, an electronically stored document 210such as that depicted in FIG. 2 may be, for example, an expense reportspreadsheet prepared by Individual 1. In this exemplary scenariodepicted in FIG. 2, Individual 1 prepares the electronically storeddocument (i.e., expense report) and in so doing creates three separatesignature lines 220, 221, and 222 in the electronically stored document210 namely, one for herself, one for her manager, Individual 2, and onefor an accounting person, Individual 3.

Operationally, the signature lines 220, 221, and 222 are indicative thatIndividual 1 originated the electronically stored document 210, and thatno changes will occur in this electronically stored document 210 as itmoves to her manager, Individual 2 and subsequently to the accountingperson, Individual 3. Additionally, such signature lines 220, 221, 223are used to verify that both the manager Individual 2 and the accountingperson Individual 3 have received and reviewed the electronically storeddocument 210.

Accordingly, after Individual 1 originates the electronically storeddocument 210 and applies her electronic signature 224, she forwards itto her manager, Individual 2. Once the manager Individual 2 receives theelectronically stored document 210, she adds her electronic signature225 to the document confirming that she has reviewed it and approved it.She then forwards the electronically stored document 210 to theaccounting person Individual 3 for electronic signature and payment. Theaccounting person Individual 3 receives the document and electronicallysigns it with her electronic signature 226, which confirms her receiptand approval and authorizes its payment.

As may be appreciated from this exemplary scenario depicted in FIG. 2,multiple electronic signatures applied to a single electronic documenthave great utility. As noted previously however, changes or revisions tothe document are generally not permitted after that electronic signature224 of Individual 1 is applied to the electronically stored document220.

As may be further appreciated by those skilled in the art, contemporarypreparation of electronically stored documents may involve thecollaboration of or coauthoring with, of a number of people. This isparticularly true for the preparation of an electronically storeddocument in a networked or cloud environment. Accordingly, such anelectronically stored document may proceed through a number of revisions(or versions), and in particular if that electronically stored documentis modified by multiple collaborators or coauthors.

Revisioning, or versioning, is a known management technique for anelectronically stored document that is changed over time. It isparticularly useful in those situations in which a number of differentpersons or teams may make changes to the electronically stored document.Frequently, it is used with respect to word processing as well ascomputer software source code version control programs.

Operationally, changes made to an electronically stored document whenrevisioning is employed are oftentimes identified by a number or lettercode, termed the “revision number”, “revision level” or simply“revision”. For example an initial electronically stored document (or aset of files) may be designated “revision 1”. When a first change (orset of changes) is made to that initial electronically stored document,the resulting document may be designated as “revision 2”, and so on.Those skilled in the art will appreciate that while the initialelectronically stored document has been referred to as “revision 1”, itshould be readily apparent that it could have been referred to as“revision 0”, or “revision A”, etc., and any subsequent revisiondesignations incremented and/or updated accordingly.

In the context of electronic signatures as described previously, it isnoted that subsequent revisions to an electronically signed,electronically stored document are not generally permitted in the priorart once an initial electronic signature is applied to theelectronically stored document.

With these general principles in place, we may now provide somenon-limiting, illustrative examples that illustrate several operationalaspects of various alternative embodiments of the present disclosurewherein revision-specific electronic signatures are applied toelectronically stored documents.

Example 1

With reference to FIG. 3, there is shown a schematic diagram depictingthe application of a revision specific electronic signature to anelectronically stored document according to an aspect of the presentdisclosure. As shown therein, an electronically stored document 310-0 isdepicted as being prepared by, and having a signature line 320 forsigning by an individual 330.

In this example shown in FIG. 3, the individual 330 prepares theelectronically stored document 310-0 at revision 0, and applies hiselectronic signature 325-0 to the signature line 320.

Recognizing that a number of changes must be made to the electronicallystored document 310-0 after applying his electronic signature 325-0, theindividual 330 makes changes to the electronically stored document 310-0such that a revision 1 of the document 310-1 is produced.

As may be readily appreciated by those skilled in the art, theelectronic signature 325-0 applied to revision 0 of the electronicallystored document 310-0 is not applicable to the changes that resulted inthis revision 1 of the electronically stored document 310-1. Accordingto an aspect of the present disclosure however, the individual may applyanother electronic signature 325-1 to this revision 1 of theelectronically stored document 310-1 such that it too is electronicallyexecuted/signed. In that regard, electronic signature 325-1 applied tothis revision 1 of the electronically stored document 310-1 is revisionspecific. More particularly, electronic signature 325-1 is specific tothis revision 1 electronically stored document 310-1. Similarly,electronic signature 325-0 is specific to revision 0 electronicallystored document 325-0.

As may be further appreciated by those skilled in the art, eachindividual revision of an electronically stored document such as thoseillustratively depicted in FIG. 3 may be associated with a timestamp andan identification of a person making changes. Persons making thechange(s) may then advantageously apply a revision specific electronicsignature to the electronically stored document. Revisions may then beadvantageously compared, restored or even merged with one another andthe revision specific electronic signatures are maintained with respectto the particular revision.

It is noted that a variety of mechanisms may be employed to indicate toan individual who is revising a particular electronically-storeddocument any status associated with a particular electronic signature.For example, moving a cursor or other visual indicator over a particularsignature may result in a “pop-up” or “balloon” or “callout” whichindicates any revision of the electronically stored document to whichthe electronic signature is applicable. Additionally, an electronicsignature that is applicable to an earlier revision of an electronicallystored document but not a current revision may be “greyed” or otherwisevisually indicative of its revision specificity.

Example 2

Turning now to FIG. 4, there is shown an additional example of anelectronically stored document having revision specific electronicsignatures applied thereto according to yet another aspect of thepresent disclosure.

In this particular example, the electronically stored document 410-0 isdepicted as being initially prepared by individual 430 and includes anumber of signature lines 420 and 421 for signing by the individual 430and her manager 440. After initial preparation by individual 430, theelectronically stored document 410-0 is at revision level 0.

In this example shown in FIG. 4, the individual 430 prepares theelectronically stored document 410-0 at revision 0, and applies herrevision-specific electronic signature 425-0 to the signature line 420.The electronically signed, electronically stored document 410-0 is thenforwarded to her manager 440 for review and signature.

Upon review of the electronically signed, electronically stored document410-0 the manager 440 notices a number of changes that must be made tothe electronically stored document 410-0. Advantageously, and accordingto an aspect of the present disclosure, the manager 440 makes anynecessary changes to the electronically stored document 410-0, therebyproducing a revision 1 electronically stored document 410-1. The managerthen electronically signs revision 1 of the electronically storeddocument 410-1 with his electronic signature 426-1.

As previously noted and according to an aspect of the presentdisclosure, once a later revision is made to an electronically signed,electronically stored document, any previously applied electronicsignatures are no longer effective/applicable for that later revision.With respect to the present Example 2 depicted in FIG. 4, the manager'selectronic signature 426-1 is effective for this revision 1 of theelectronically stored document 410-1, while the originator's revision 0electronic signature 425-0, is not.

Accordingly, and while not specifically depicted in FIG. 4, any of avariety of visual indicators may be used to visually identify theeffectiveness of an applied electronic signature. For example, anelectronic signature that is no longer effective may be shown as“greyed”, or “dotted”, or “ghosted” or “blinking” or a combinationthereof or other visual indicators.

Returning now to our discussion of FIG. 4 and the Example depictedtherein, after manager 440 applies his revision specific electronicsignature 426-1 to revision 1 electronically stored document 410-1, itis then returned to originator 430 for review and approval. Accordingly,once originator 430 reviews and approves this revision 1 electronicallystored document 410-1, she applies her revision specific electronicsignature 425-1 to the document 410-1. She may then forward it (or not)as her needs dictate. It is noted that according to an aspect of thepresent disclosure, electronically stored documents may advantageouslybe viewed by one or more users in a viewing mode that shows/highlightschanges/markup. In this manner, any differences in the electronicallystored document between revisions may be highlighted or otherwiseidentified to aid a user in review. Accordingly, a subsequent reviewinguser may observe/review only those portions of an electronically storeddocument which has changed from a previous revision(s) and then apply anelectronic signature, as appropriate.

At this point it should be apparent to those skilled in the art that theapplication of revision specific electronic signatures such as thosedepicted in this Example 2 may advantageously eliminate redundantreviews of electronically stored documents. For example, after theoriginator 430 applied revision specific electronic signature 425-1 torevision 1 of the electronically stored document 410-1, it did not haveto return to the manager 440 for review and approval.

Example 3

With reference now to FIG. 5, there is shown an additional example of anelectronically stored document having revision specific electronicsignatures applied thereto according to yet another aspect of thepresent disclosure.

In this particular example, the electronically stored document 510-0 isdepicted as being initially prepared by individual 530 and includes anumber of signature lines 520 and 521 for signing by the individual 530and her manager 540. After initial preparation by individual 530, theelectronically stored document 510-0 is at revision level 0.

In this example shown in FIG. 5, the individual 530 prepares theelectronically stored document 510-0 at revision level 0, and appliesher revision-specific electronic signature 525-0 to the signature line520. The electronically signed, electronically stored document is thenforwarded to her manager 540 for review and signature.

Upon review of the electronically signed, electronically stored document510-0 the manager 540 begins making a number of changes to theelectronically stored document 510-0. As noted previously, upon makingthe changes the electronically stored document proceeds to a revisionlevel 1, and as such the previously applied revision specific electronicsignature 525-0 applied by originating individual 530 is no longereffective for the revision level 1.

Notwithstanding these initial changes, the manager 540 reconsiders hischanges and subsequently changes the electronically stored document backto its revision level 0. According to an aspect of the presentdisclosure, the previously applied revision level 0 signature 525-0applied by originating individual 530 is once again effective.Consequently, the manager 540 now applies his revision specificelectronic signature 526-0 to this revision 0 document 510-0 andforwards it—or not—as appropriate. The resulting electronically storeddocument depicted in this example is a revision 0 electronically storeddocument having two effective, revision-specific electronic signaturesapplied thereto namely, 525-0, and 526-0.

At this point we note that an additional aspect of revision-specificelectronic signatures as applied to electronically stored documentsaccording to another aspect of the present disclosure. Moreparticularly, it is noted that when a revision specific electronicsignature such as 525-0 is applied to an electronically stored document510-0, it may advantageously be marked or otherwise identified as havinga period of time during which it remains effective. That is to say, anelectronic signature such as 525-0 may become “stale” upon theexpiration of a pre-determined period of time after which the signatureis determined to be “stale” and therefore no longer effective.Advantageously, such an expiration period may be set to any of a varietyof user definable periods, namely, hours, days, weeks, etc. In thismanner, once an electronic signature is applied to an electronicallystored document, subsequent reviewers may be “urged” to expeditiouslycomplete their review/execution before previously applied signaturesexpire. Notably, and according to another aspect of the presentdisclosure, upon the application of all required electronic signaturesany pre-determined expiration periods are disabled. In other words, ifall required subsequent electronic signatures are applied before theexpiration of the pre-determined period of time for a previously appliedelectronic signature, then the expiration period for the previouslyapplied electronic signature is disabled and the period of time iseffectively an indefinite one and the signatures will always be validand effective.

Notably, color or other visual indicator may be used to indicate whetheror not a particular signature is effective and/or whether it is becomingstale. More particularly, and by way of example only and in no waylimiting, a valid electronic signature that either does not expire or isnot within a pre-determined period of expiring, may be displayed asgreen. Similarly, an expired, stale, or otherwise invalid or ineffectiveelectronic signature may be displayed in red. Finally, an electronicsignature that is within a pre-determined period of expiring or becomingstale may be displayed in yellow. Those skilled in the art willappreciate that other visual indicators are contemplated as well.

FIG. 6(a) depicts a schematic illustration of an electronically storeddocument at a revision level 1 600-1, having a number of revisionspecific electronic signatures attached thereto 625-0, 625-1, 626-1.Since the electronically stored document 600-1 is at revision level 1 inthis illustration, the revision 0 specific electronic signature 625-0 isshown as behind the revision 1 specific electronic signature 625-1.Those skilled in the art will appreciate that this depiction is merelyone illustrative example of how such multiple revision-specificelectronic signatures may be depicted for an individual signor orgenerally.

Shown further in this FIG. 6(a), are several “callouts” or “balloons”627, 628, and 629 which may result for example, when a cursor or otheruser input structure is hovered over the particular electronicsignature. Alternatively, such callouts may be invoked by touching atouch sensitive display device. As shown in this example, the callouts627, 628, 629 provide information about the particular electronicsignature 625-0, 625-1, and 626-1 to which they are associated.

For example, the callout associated with revision specific signature625-0, namely 627, indicates the person who applied the signature, thedate, time, document and revision number of the document. Likewise,similar information is viewable from callouts associated with laterrevision specific signatures 625-1, 626-1, namely, 628 and 629.

Those skilled in the art will appreciate that revision specificinformation (shown in callouts 627, 628, and 629) associated with eachof the revision specific electronic signatures 625-0, 625-1, 626-1depicted in this FIG. 6(a) are not necessarily “attached” to or“carried” by the electronic signatures themselves. In this regard, aspecific electronically stored document may advantageouslymaintain/store its revision information distinctly from information ofthe original document and associate a particular electronically storeddocument revision to a particular electronic signature. According to anaspect of the present disclosure then, an association is made betweenthe revision level of the electronically stored document and aparticular electronic signature and that association may bemaintained/stored either by the electronically stored document itself,the electronic signature, or another electronically-stored structure.

With reference now to FIG. 6(b) there is shown the electronically storeddocument 610-1 depicted in FIG. 6(a) where the revision history isviewed as a callout 699 in tabular form. As may be appreciated by thoseskilled in the art, a right-click or other enabling action mayadvantageously invoke such callout 699 which—by way of exampleonly—displays the revision number, action taken, when taken, by whotaken, and whether or not an electronic signature was applied. In thismanner, subsequent reviewers can quickly and effectively assess apresent status of the electronically stored document and in particularwith respect to any electronic signatures.

With these aspects in mind, we now disclose an exemplary scenario forattaching a revision-specific electronic signature to an electronicallystored document. Of particular interest and according to yet anotheraspect of the present disclosure, revision specific electronicsignatures may be applied to electronically stored documents via localdevices, i.e., personal computers, laptop computers, personal digitalassistants (PDAs), smartphones, tablet computers and the like, as wellas via networks or via clouds.

With reference now to FIG. 7, there is shown a series of illustrationsdepicting one of many possible ways in which revision specificelectronic signatures may be applied to an electronically storeddocument. As depicted in that FIG. 7, an electronically stored document710 is shown as having a signature line 720.

A user 730 may then “right click” or otherwise indicate that a revisionspecific electronic signature is to be applied 740 producing a challengedialogue box 750 into which the user 730 inputs a password 760 or otherresponse to the challenge. If the response 760 is acceptable accordingto some predetermined standard, then the revision specific electronicsignature 770 is applied to the electronically stored document 710.Advantageously, and as may be readily appreciated by those skilled inthe art, the challenge 760 presented to the user 730 may require ausername or other indicia of user as well. Notably, such userauthentication may be provided by any of a number of known methods andinput devices including keystroke, mouse input, biometric, fingerprint,RFID, smartcard and the like.

Alternatively, it is noted that in certain situations a user 730 may bepreparing the electronically stored document 710 within a network orcloud computing environment (not specifically shown). In such acircumstance, and as can be readily appreciated by those skilled in theart, a challenge (i.e., username/password) or other authenticationscheme (i.e., challenge, biometric, etc.) may have been employed topermit the user 730 to access the network and/or cloud.

Advantageously, and according to yet another aspect of the presentdisclosure, where a user 730 has already provided sufficientauthentication (logged-in-credentials) then applying the electronicsignature 770 may not require an additional challenge such as that shownin FIG. 7. In such a situation, the user may just right-click orotherwise indicate the application of an electronic signature forexample, via a check-box, a menu, a dialogue box, a checkbox,pushbutton, radiobutton, etc. Notwithstanding this aspect however,additional security characteristics may be achieved through the use ofthe challenges/passwords described herein, prior to applying anelectronic signature and particular implementations may benefit fromsuch characteristics. Accordingly, the present disclosure is not limitedto a particular user authentication/credential scheme.

Advantageously, an electronically stored document 710 such as thatdepicted in FIG. 7 may be stored locally or remotely in a network orcloud. Similarly, any revision specific electronic signatures may belikewise stored and subsequently applied as individual users require.

FIG. 8 shows an illustrative computer system 800 suitable forimplementing methods and systems according to an aspect of the presentdisclosure. The computer system may comprise, for example a computerrunning any of a number of operating systems. The above-describedmethods of the present disclosure may be implemented on the computersystem. 800 as stored program control instructions.

Computer system 800 includes processor 810, memory 820, storage device830, and input/output structure 840. One or more input/output devicesmay include a display 845. One or more busses 850 typically interconnectthe components, 810, 820, 830, and 840. Processor 810 may be a single ormulti core.

Processor 810 executes instructions in which embodiments of the presentdisclosure may comprise steps described in one or more of the Figures.Such instructions may be stored in memory 820 or storage device 830.Data and/or information may be received and output using one or moreinput/output devices.

Memory 820 may store data and may be a computer-readable medium, such asvolatile or non-volatile memory. Storage device 830 may provide storagefor system 800 including for example, the previously described methods.In various aspects, storage device 830 may be a flash memory device, adisk drive, an optical disk device, or a tape device employing magnetic,optical, or other recording technologies.

Input/output structures 840 may provide input/output operations forsystem 800. Input/output devices utilizing these structures may include,for example, keyboards, displays 845, pointing devices, andmicrophones—among others. As shown and may be readily appreciated bythose skilled in the art, computer system 800 for use with the presentdisclosure may be implemented in a desktop computer package 860, alaptop computer 870, a hand-held computer, for example a tabletcomputer, personal digital assistant or smartphone 880, or one or moreserver computers which may advantageously comprise a “cloud” computer890.

At this point, while we have discussed and described the invention usingsome specific examples, those skilled in the art will recognize that ourteachings are not so limited. Accordingly, the invention should be onlylimited by the scope of the claims attached hereto.

The invention claimed is:
 1. A computer-implemented method forelectronically signing an electronically stored document that includesdocument content, comprising the steps of: providing at least a firstuser and a second user remote access to the electronically storeddocument; applying, by one or more processors, a first electronicsignature to the electronically stored document to produce an initialsigned version of the electronically stored document, wherein the firstelectronic signature includes information that associates the firstelectronic signature with the initial signed version of theelectronically stored document, the first electronic signature verifiesintegrity of the document content of the initial signed version of theelectronically stored document, and the first electronic signatureincludes a first cryptographic component; subsequent to applying thefirst electronic signature to the electronically stored document,modifying, by the one or more processors, the document content of theinitial signed version of the electronically stored document therebyproducing a first revision of the electronically stored document;subsequent to modifying the initial signed version of the electronicallystored document, applying, by the one or more processors, a secondelectronic signature to the first revision of the electronically storeddocument, wherein the second electronic signature includes informationthat associates the second electronic signature with the first revisionof the electronically stored document, the second electronic signatureverifies integrity of the document content the first revision of theelectronically stored document, and the second electronic signatureincludes a second cryptographic component; and generating a revisionhistory of the electronically stored document, wherein the revisionhistory associates the first electronic signature with the initialsigned version of the electronically stored document and associates atleast the second electronic signature with the first revision of thefirst electronically stored document.
 2. The method of claim 1, whereinthe revision history also associates the first electronic signature withthe first revision of the electronically stored document.
 3. The methodof claim 1, wherein the first revision of the electronically storeddocument includes both the first electronic signature and the secondelectronic signature.
 4. The method of claim 1, wherein the firstelectronic signature is associated with at least one of the first useror the second user and the second electronic signature is associatedwith at least one of the first user or the second user.
 5. The method ofclaim 1, wherein the first electronic signature is associated with thefirst user and the second electronic signature is associated the seconduser.
 6. The method of claim 1, wherein the first electronic signatureand the second electronic signature are both associated with the sameuser.
 7. The method of claim 1, wherein the first electronic signatureis revoked upon modifying the electronically stored document.
 8. Acomputer-implemented system for electronically signing an electronicallystored document that includes document content and is accessible by thesystem, the system comprising: one or more processors; and one or morememory devices for storing program instructions, wherein the programinstructions, when executed by the one or more processors, cause the oneor more processors to: provide at least a first user and a second userremote access to the electronically stored document; apply a firstelectronic signature to the electronically stored document to produce aninitial signed version of the electronically stored document, whereinthe first electronic signature includes information that associates thefirst electronic signature with the initial signed version of theelectronically stored document, the first electronic signature verifiesintegrity of the document content of the initial signed version of theelectronically stored document, and the first electronic signatureincludes a first cryptographic component; subsequent to application ofthe first electronic signature to the electronically stored document,modify the document content of the initial signed version of theelectronically stored document thereby producing a first revision of theelectronically stored document; subsequent to modification of thedocument content of the initial signed version of the electronicallystored document, apply a second electronic signature to the firstrevision of the electronically stored document, wherein the secondelectronic signature includes information that associates the secondelectronic signature with the first revision of the electronicallystored document, the second electronic signature verifies integrity ofthe document content of the first revision of the electronically storeddocument, and the second electronic signature includes a secondcryptographic component; and generate a revision history of theelectronically stored document, wherein the revision history associatesthe first electronic signature with the initial signed version of theelectronically stored document and associates at least the secondelectronic signature with the first revision of the first electronicallystored document.
 9. The m computer-implemented system method of claim 8,wherein the revision history also associates the first electronicsignature with the first revision of the electronically stored document.10. The computer-implemented system of claim 8, wherein the firstrevision of the electronically stored document includes both the firstelectronic signature and the second electronic signature.
 11. Thecomputer-implemented system of claim 8, wherein the first electronicsignature is associated with at least one of the first user or thesecond user and the second electronic signature is associated with atleast one of the first user or the second user.
 12. Thecomputer-implemented system of claim 8, wherein the first electronicsignature is associated with the first user and the second electronicsignature is associated the second user.
 13. The computer-implementedsystem of claim 8, wherein the first electronic signature and the secondelectronic signature are both associated with the same user.
 14. Thecomputer-implemented system of claim 8, wherein the first electronicsignature is revoked upon modifying the electronically stored document.15. A non-transitory computer storage medium having computer executableinstructions which when executed by a computer cause the computer toperform operations comprising: providing at least a first user and asecond user remote access to an electronically stored document thatincludes document content; applying a first electronic signature to theelectronically stored document to produce an initial signed version ofthe electronically stored document, wherein the first electronicsignature includes information that associates the first electronicsignature with the initial signed version of the electronically storeddocument, the first electronic signature verifies integrity of thedocument content of the initial signed version of the electronicallystored document, and the first electronic signature includes a firstcryptographic component; subsequent to applying the first electronicsignature to the electronically stored document, modifying the documentcontent of the initial signed version of the electronically storeddocument thereby producing a first revision of the electronically storeddocument; subsequent to modifying the document content of the initialsigned document, applying a second electronic signature to the firstrevision of the electronically stored document, wherein the secondelectronic signature includes information that associates the secondelectronic signature with the first revision of the electronicallystored document, the second electronic signature verifies integrity ofthe document content of the first revision of the electronically storeddocument, and the second electronic signature includes a secondcryptographic component; and generating a revision history of theelectronically stored document, wherein the revision history associatesthe first electronic signature with the initial signed version of theelectronically stored document and associates at least the secondelectronic signature with the first revision of the first electronicallystored document.
 16. The non-transitory computer storage medium of claim15, wherein the revision history also associates the first electronicsignature with the first revision of the electronically stored document.17. The non-transitory computer storage medium of claim 15, wherein thefirst revision of the electronically stored document includes both thefirst electronic signature and the second electronic signature.
 18. Thenon-transitory computer storage medium of claim 15, wherein the firstelectronic signature is associated with at least one of the first useror the second user and the second electronic signature is associatedwith at least one of the first user or the second user.
 19. Thenon-transitory computer storage medium of claim 15, wherein the firstelectronic signature is associated with the first user and the secondelectronic signature is associated the second user.
 20. Thenon-transitory computer storage medium of claim 15, wherein the firstelectronic signature and the second electronic signature are bothassociated with the same user.
 21. The non-transitory computer storagemedium of claim 15, wherein the first electronic signature is revokedupon modifying the electronically stored document.